In recent years demands for large-volume and high-speed information transmission have increased and optical fiber communication networks have been provided in office buildings and general homes. In the case of drawing an optical fiber into a home from a trunk line, for example, it is necessary to splice the optical fiber on the side of the trunk line and an optical fiber in the home. Optical fibers are spliced together in the following manner: first, glass fiber portions are exposed by removing the covering of the respective optical fibers; the exposed glass fiber portions are cut; and the cut end faces of the glass fiber portions are butted each other so as to be spliced together.
In the fiber cleavers for cutting a glass fiber portion as disclosed in Japanese Patent Application Publication No. Tokukai 2003-165740 and Japanese Patent Application Publication No. Tokukai-Hei-9-90136, an initial scratch is afforded to the surface of a glass fiber portion and the part including the scratch is pressed so as to cause the initial scratch to develop such that the glass fiber portion is cleaved at the position of the initial scratch.
FIG. 19 is a side view of the fiber cleaver disclosed in Japanese Patent Application Publication No. 2003-165740. For cutting a glass fiber portion using a cleaver 200, first an optical fiber is held by a holder 201 in the state of the glass fiber portion being exposed protruding from the end of the optical fiber, and the holder 201 is mounted on the main body 202. Thus, the glass fiber portion is positioned on a pair of lower holding parts 203. Next, an operator manually closes a cover 204 provided at an upper position of the main body 202 so that the glass fiber portion is fixed by the pair of lower holding parts 203 and a pair of upper holding parts 205 provided in the cover 204.
Subsequently, the operator manually moves the cutter 206, which is provided between the pair of upper holding parts 205 and the pair of lower holding parts 203, in a direction perpendicular to the longitudinal direction of the glass fiber portion so that the movement of the cutter 206 affords an initial scratch to the surface of the glass fiber portion. Subsequently, as a result of a breaker 230 pressing the part including the initial scratch, the scratch is developed so as to break the glass fiber portion at the position of the initial scratch. Closing the cover 220 causes the unnecessary broken piece of the glass fiber portion to be inserted between the upper and lower guide rollers 207. In this state, the operator manually turns the upper and lower guide rollers 207 to convey the unnecessary piece, which has been inserted between the upper and lower guide rollers 207, to a storage part 209.
In the case of cleaving a glass fiber portion with the fiber cleaver 200, the movement of the cutter 206, the opening and shutting of the cover 220, and the turning of the upper and lower guide rollers 207 must be performed manually, which results in the hindrance to shortening the cleaving work. Also, it is difficult to achieve satisfactory reproducibility in cleaving performance because the movement speed of the cutter 206 differs depending on an operator.
In addition, the method disclosed in Japanese Patent Application Publication No. 2003-165740 has the step of holding an optical fiber at the holder 201 before the step of cutting the glass fiber portion. In the holding step, the optical fiber is held by the holder 201 after the length of the optical fiber portion that protrudes from the holder 201 has been adjusted according to the manner in which the glass fiber portion is subsequently processed. The optical fiber held by the holder 201 is processed so that the protective covering of the optical fiber is removed on the tip side thereof with the pre-determined length from the tip of the holder 201 being left as it is, whereby a glass fiber portion without the protective covering is obtained. Thereafter, the glass fiber portion is cut to the predetermined length using the above mentioned cleaver and so on.
Once an optical fiber is held by the holder 201, it is set to the cleaver or splicer without removing the optical fiber from the holder 201, and the processing work in the subsequent cleaving step and the step of splicing with another optical fiber is performed in that state. Therefore, the length of the optical fiber having its protective covering that protrudes from the holder 201 is determined by the setting conditions of these devices. For example, in the case of fusion-splicing of glass fibers, the protruding portion having a protective covering is usually short comparatively, and in the case of mechanical splicing of glass fibers without making fusion-splice, the protruding portion having a protective covering is long.
In the cleaver 200, the position at which the holder is mounted is predetermined, and the holder 201 is fixed at the predetermined position on the main body 202, and the glass portion is cut. In this case, since the pre-determined fixing position does not agree with the cleaving position, in order to increase the length of the portion having the protective covering that protrudes from the holder 201, a spacer and the like is arranged so that the holder 201 is fixed through the spacer such that the distance between the holder 210 and a cutting blade 206 is adjusted accordingly. A distance adjusting member such as the spacer is small, and the setting work in the cleaver tends to take time. Also, it may be necessary to prepare more than one kind of spacers according to the various lengths in which optical fibers protrude from the holder, and the safekeeping of a plurality of spacers is burdensome. Moreover, since the spacers are small, careful attention is needed so that they may not be lost.
Patent literature 1: Japanese Patent Application Publication No. Tokukai 2003-165740
Patent literature 2: Japanese Patent Application Publication-No. Tokukai-Hei 9-90136